Chemistry - Atomic structure and the periodic table - Group 7 Halogens

Question 1

What are the three common Halogens in group 7?

Answer 1

Chlorine, Bromine and iodine.

Question 2

What properties do chlorine, bromine and iodine have in common?

Answer 2

They’re toxic - kill bacteria.

Question 3

What is the appearance and typical use of chlorine?

Answer 3

Yellow/green gas - Sterilising water

Question 4

What is the appearance of bromine?

Answer 4

Red/Brown liquid

Question 5

What is the appearance and typical use of iodine?

Answer 5

Grey solid (forms purple vapour when warmed) - Antiseptic used during hospital procedures

Question 6

Why are group 7 elements halogens?

Answer 6

Group 7 elements form salts when they react with metals. The term ‘halogen’ means ‘salt former

Question 7

What are the melting points of group 7 halogens?

Answer 7

The halogens have low melting points and low boiling points. They increase as you go down the group.

Question 8

What are the states of group 7 elements at room temperature?

Answer 8

Fluorine - Gas
Chlorine - Gas
Bromine - Liquid
Iodine - Solid
Astatine - Solid

Question 9

How do the halogens colours change as you go down the group?

Answer 9

The halogens become darker as you go down the group.

Question 10

How does the reactivity change as you go down group 7?

Answer 10

The elements get less reactive. Opposite to Group 1

Question 11

How does fluorine react with iron wool?

Answer 11

Reacts with almost anything instantly. Very few scientists handle fluorine because it is so dangerous. Produces iron(III) fluoride.

Question 12

How does chlorine react with iron wool?

Answer 12

Reacts with heated iron wool very quickly, although not as quickly as fluorine does. Produces iron(III) chloride.

Question 13

How does bromine react with iron wool?

Answer 13

Has to be warmed and the iron wool heated. The reaction is faster than that of iodine but slower than that of chlorine. Produces iron(III) bromide.

Question 14

How does iodine react with iron wool?

Answer 14

Has to be heated strongly and so does the iron wool. The reaction is slow. Produces iron(III) iodide.

Question 15

How does displacement happen?

Answer 15

Example : When chlorine is added to sodium bromide solution, the chlorine takes the place of the bromine. Because chlorine is more reactive than bromine, it displaces bromine from sodium bromide.

Question 16

What is a redox reaction?

Answer 16

Redox reactions involve both oxidation (loss of electrons) and reduction (gain of electrons). You could remember it as OIL RIG – Oxidation Is Loss of electrons, Reduction Is Gain of electrons.